1. Field of the Invention
The present invention relates to a power supply shut-off apparatus for electrically interrupting the connection between a power supply and a load, and more particularly, to a small and space-saving power supply shut-off apparatus in which a fitting-detection ability is enhanced, the number of parts is small and cost-reduction can be realized.
2. Description of the Related Art
For example, in the case of an electric car, since a capacity of a power supply which is a battery is great as compared with that of a gasoline engine car, for maintenance of its electrical system, a power supply shut-off apparatus is provided for ensuring safety of operation.
As such a power supply shut-off apparatus, one as disclosed in Japanese Patent Application Laid-open No.H9-265874 is known for example. As shown in FIGS. 1 and 2, this power supply shut-off apparatus comprises a shut-off apparatus body 501, and a service plug 502 which is detachable and attachable with respect to the shut-off apparatus body 501.
As shown in FIG. 1, the shut-off apparatus body 501 includes a lower casing 503 and an upper casing 504 mounted on an upper end of the lower casing 503. Accommodated in the lower casing 503 are a pair of stationary electrodes 505, 506, a fuse 507, a terminal hardware 509 of a power supply-side wire 508 connected to the one stationary electrode 505, a terminal hardware 512 of a load-side wire 511 connected to one terminal 510 of the fuse 507, and a bus bar 514 for connecting the other terminal 513 of the fuse 507 and the other stationary electrode 506.
As shown in FIG. 1, the stationary electrodes 505 and 506 are threadedly engaged with and vertically rising from female screw members 515, 515 formed by insert molding such as to be embedded in the lower casing 503 at a predetermined distance from each other. The upper casing 503 is formed with circular holes 516, 516 at locations corresponding to the stationary electrodes 505, 506, and the stationary electrodes 505, 506 faces the circular holes 516, 516.
As shown in FIGS. 1 and 2, the service plug 502 comprises a movable electrode 518 having a pair of louver terminals 517, 517 mounted to the pair of stationary electrodes 505, 506 through the circular holes 516, 516, a handle mounting body 519 for mounting the movable electrode 518, a handle 521 supported such that the handle 521 can turn around a turning-movement supporting shaft 520 with respect to the handle mounting body 519, a spring member 522 provided between the handle 521 and the handle mounting body 519 for holding the handle 521 using toggle effect between a state where the handle 521 rises vertically and a state where the handle 521 lies horizontally, and magnets 524, 524 provided in the handle 521 and opposed to lead switch 523 provided on the upper casing 504 when the handle 521 is tilted down horizontally.
In the power supply shut-off apparatus constituted in the above manner, as shown in FIG. 1, if the pair of louver terminals 517, 517 are inserted into the circular holes 516, 516 formed in the upper casing 504 and are fitted to the stationary electrodes 505, 506 in a state where the handle 521 vertically stands up, the terminal hardware 509 of the power supply-side wire 508 and the terminal hardware 512 of the load-side wire 511 are electrically connected while the fuse 507 is arranged in series.
Then, the handle 521 is horizontally tilted down as shown in FIG. 2. With this, the magnets 524 provided in he handle 512 are disposed such as to be opposed to the lead switch 523, the conductive state between the terminal hardware 509 of the power supply-side wire 508 and the terminal hardware 512 of the load-side wire 511 is detected, and the detection result is transmitted to a computer.
According to the power supply shut-off apparatus constituted in this manner, by forming the service plug 502 such that it can be attached to and detached from the shut-off apparatus body 501, the terminal hardware 509 of the power supply-side wire 508 and the terminal hardware 512 of the load-side wire 511 can easily be electrically connected or disconnected. Therefore, the operation safety at the time of maintenance of the electrical system in an electric car for example can be ensured.
However, in the power supply shut-off apparatus of the above structure, the number of parts constituting the shut-off apparatus body 501 and a service plug 502 is great, the apparatus itself is increased in size, and an installation space must be ensured sufficiently. Especially, the structure of the service plug 502 is complicated, and this is disadvantageous in terms of the cost.
Further, in the above power supply shut-off apparatus, when the service plug 502 is mounted to the shut-off apparatus body 501, since it is necessary to insert and fit the louver terminals 517, 517 into the circular holes 516, 516 formed in the upper casing 504, this mounting operation of the service plug 502 is not easy. Especially when the power supply shut-off apparatus is mounted to a place where an operator can not easily to see, the mounting operation of the service plug 502 to the shut-off apparatus body 501 becomes more difficult.
It is an object of the present invention to provide a small and space-saving power supply shut-off apparatus in which a fitting-detection ability is enhanced, the number of parts is small and cost-reduction.
To achieve the above object, a power supply shut-off apparatus of the present invention comprises: an apparatus body including, bus bar mounting portions for respectively mounting one bus bar and another bus bar, a fuse mounting portion for mounting a fuse having one fuse terminal connected to a terminal of the one bus bar and having another fuse terminal connected to a one side edge terminal of an intermediate bus bar, a plug mounting portion which accommodates a terminal holding member in which a terminal of the other bus bar and the other side edge terminal of the intermediate bus bar are disposed on the opposite sides with respect to an insulation wall, and which is formed of a partition wall surrounding an outer periphery of the terminal holding member, and a conduction detecting means mounting portion for mounting conduction detecting means which detects a conduction state in which the one bus bar and the other bus bar are in conduction through the fuse and a nonconduction state therebetween; and a service plug including, a plug housing having a terminal member which is detachably mounted to the plug mounting portion and which is mounted astride the terminal holding member to come contact with the terminal of the other bus bar and to come contact with the terminal of the other side edge of the intermediate bus bar, thereby bringing the one bus bar and the other bus bar into conduction, and a service plug comprising a tilting lever which is tiltable between a substantially vertical state and a substantially horizontal state with respect to the plug housing; wherein when the plug housing is mounted to the plug mounting portion and the tilting lever is tilted down substantially horizontally in a state where the tilting lever of the service plug is held in the substantially vertical state, a projection provided on the tilting lever falls a movable lever of the conduction detecting means so as to allow the conduction detecting means to detect the conduction state between the one bus bar and the other bus bar.
In this manner, the terminal holding member in which a terminal of the other bus bar and the other side edge terminal of the intermediate bus bar are disposed on the opposite sides of an insulation wall is provided in the plug mounting portion which mounts the service plug to the apparatus is body, the plug housing having a terminal member which is mounted astride the terminal holding member and which comes into contact with the terminal of the other bus bar and the other side edge terminal of the other bus bar to bring the one bus bar and the other bus bar into conduction is mounted to the plug mounting portion. Therefore, the terminal holding member serves as a guide, and even if the power supply shut-off apparatus is disposed in a place where the operation is difficult, the service plug can easily be mounted.
Further, since the tilting lever is tiltably mounted to the plug housing, when the service plug is mounted to or removed from the plug mounting portion, the plug can easily be mounted by holding the tilting lever.
Further, when the plug housing is mounted to the plug mounting portion and the tilting lever is tilted down substantially horizontally in a state where the tilting lever of the service plug is held in the substantially vertical state, the projection provided on the tilting lever falls the movable lever of the conduction detecting means so as to allow the microswitch to detect the conduction state between the one bus bar and the other bus bar. Therefore, even if the plug housing is fitted to the plug mounting portion and the one bus bar and the other bus bar are brought into conduction, this conduction state is not detected by the microswitch unless the tilting lever is tilted horizontally to fall the movable lever. Thus, after the one bus bar and the other bus bar are brought into conduction, it is possible for an operator to allow the microswitch to detect the conduction state with a time lag intentionally, and it is possible to avoid an influence of remaining current.
Further, in the power supply shut-off apparatus of the present invention, the terminal holding member is formed with a pick-up slanting surface for mounting the terminal member.
Since the terminal holding member is formed with the pick-up slanting surfaces and, the terminal member provided on the plug housing is guided by the terminal holding member and smoothly mounted, which makes it easy to mount the service plug to the plug mounting portion.
Further, in the power supply shut-off apparatus of the present invention, the plug housing is provided with a projection which prevents the tilting lever from tilting to the horizontal direction by abutting the tilting lever against an inner surface of the partition wall of the plug mounting portion when the tilting lever is tilted to the horizontal direction in an incomplete mounting state in which the plug housing is not in contact with a tip end surface of the terminal holding member.
Since the tilting lever is designed such that it does not fall in the horizontal direction when the service plug is mounted incompletely, the mounting state of the service plug to the plug mounting portion can be judged instantaneously, and it is possible to avoid the incomplete mounting of the service plug.
Further, in the power supply shut-off apparatus of the present invention, the apparatus body is provided with an insulation cover for covering the fuse and the conduction detecting means, and the insulation cover is pushed by a cover pushing portion provided on the plug housing.
Therefore, the insulation cover can not be detached unless the service plug is detached from the plug mounting portion and thus, the safety can be ensured.
Further, in the power supply shut-off apparatus of the present invention, the conduction detecting means is a microswitch.
Since the microswitch is small in size and inexpensive, the mounting space can be small, and the power supply shut-off apparatus can be reduced in both size and cost.